1、 AMERICAN NATIONAL STANDARD ANSI/ISA96.03.022015 Guidelines for the Specification of Pneumatic Rack and Pinion Valve Actuators Approved 28 July 2015 ANSI/ISA-96.03.02-2015 Guidelines for the Specification of Pneumatic Rack and Pinion Valve Actuators ISBN: 978-1-941546-67-3 Copyright 2015 by the Inte
2、rnational Society of Automation (ISA). All rights reserved. Not for resale. Printed in the United States of America. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means (electronic mechanical, photocopying, recording, or otherwise),
3、 without the prior written permission of the Publisher. ISA 67 Alexander Drive P.O. Box 12277 Research Triangle Park, North Carolina 27709 - 3 - ANSI/ISA-96.03.02-2015 Copyright 2015 ISA. All rights reserved. Preface This preface, as well as all footnotes and annexes, is included for information pur
4、poses and is not part of ANSI/ISA-96.03.02-2015. This document has been prepared as part of the service of ISA toward a goal of uniformity in the field of instrumentation. To be of real value, this document should not be static but should be subject to periodic review. Toward this end, the Society w
5、elcomes all comments and criticisms and asks that they be addressed to the Secretary, Standards and Practices Board; ISA; 67 Alexander Drive; P. O. Box 12277; Research Triangle Park, NC 27709; Telephone (919) 549-8411; Fax (919) 549-8288; E-mail: standardsisa.org. The ISA Standards and Practices Dep
6、artment is aware of the growing need for attention to the metric system of units in general, and the International System of Units (SI) in particular, in the preparation of instrumentation standards. The Department is further aware of the benefits to USA users of ISA standards of incorporating suita
7、ble references to the SI (and the metric system) in their business and professional dealings with other countries. Toward this end, this Department will endeavor to introduce SI-acceptable metric units in all new and revised standards, recommended practices, and technical reports to the greatest ext
8、ent possible. IEEE/ASTM SI 10, American National Standard for Metric Practice, and future revisions, will be the reference guide for definitions, symbols, abbreviations, and conversion factors. It is the policy of ISA to encourage and welcome the participation of all concerned individuals and intere
9、sts in the development of ISA standards, recommended practices, and technical reports. Participation in the ISA standards-making process by an individual in no way constitutes endorsement by the employer of that individual, of ISA, or of any of the standards, recommended practices, and technical rep
10、orts that ISA develops. CAUTION ISA DOES NOT TAKE ANY POSITION WITH RESPECT TO THE EXISTENCE OR VALIDITY OF ANY PATENT RIGHTS ASSERTED IN CONNECTION WITH THIS DOCUMENT, AND ISA DISCLAIMS LIABILITY FOR THE INFRINGEMENT OF ANY PATENT RESULTING FROM THE USE OF THIS DOCUMENT. USERS ARE ADVISED THAT DETE
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15、 OF THE DOCUMENT NOTIFY THE ISA STANDARDS AND PRACTICES DEPARTMENT OF THE PATENT AND ITS OWNER. ANSI/ISA-96.03.02-2015 - 4 - Copyright 2015 ISA. All rights reserved. ADDITIONALLY, THE USE OF THIS DOCUMENT MAY INVOLVE HAZARDOUS MATERIALS, OPERATIONS OR EQUIPMENT. THE DOCUMENT CANNOT ANTICIPATE ALL PO
16、SSIBLE APPLICATIONS OR ADDRESS ALL POSSIBLE SAFETY ISSUES ASSOCIATED WITH USE IN HAZARDOUS CONDITIONS. THE USER OF THIS DOCUMENT MUST EXERCISE SOUND PROFESSIONAL JUDGMENT CONCERNING ITS USE AND APPLICABILITY UNDER THE USERS PARTICULAR CIRCUMSTANCES. THE USER MUST ALSO CONSIDER THE APPLICABILITY OF A
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18、The following people served as members of ISA96.03. NAME COMPANY V. Mezzano, Chair Fluor Corp. W. Weidman, Managing Director WCW Consulting M. Bober Copes-Vulcan S. Boyle Metso Automation USA Inc. K. Enos Rexa, Inc. E. Holtgraver QTRCO Inc. A. Michelson Sunbelt Supply D. Payne Pentair Valves and Con
19、trols S. Richardson Kinetrol USA Inc. S. Samy CCI K. Walker Flowserve Corp. F. Washburn Rotork Controls J. Young The Dow Chemical Company The following people served as members of ISA96. NAME COMPANY V. Mezzano, Chair Fluor Corp. W. Weidman, Managing Director WCW Consulting Y. Yermanos Oleoducto de
20、los Llanos Orientales L. Beckman Safeplex Systems Inc. M. Bober Copes-Vulcan S. Boyle Metso Automation USA Inc. K. Enos Rexa, Inc. E. Holtgraver QTRCO Inc. D. Leese Automation Technology G. Liu Consultant S. Meunier Cowan Dynamics Inc. A. Michelson Sunbelt Supply S. Samy CCI F. Washburn Rotork Contr
21、ols L. Winkel Flowserve J. Young The Dow Chemical Company - 5 - ANSI/ISA-96.03.02-2015 Copyright 2015 ISA. All rights reserved. This document was approved for publication by the ISA Standards and Practices Board on 15 July 2015. NAME AFFILIATION N. Sands, Vice President DuPont D. Bartusiak ExxonMobi
22、l Research the measure of a forces tendency to produce torsion and rotation about an axis, equal to the vector product of the radius vector from the axis of rotation to the point of application of the force and the force vector. A turning or twisting force, usually expressed in foot-pounds, inch-pou
23、nds or Newton meters. ANSI/ISA-96.03.02-2015 - 12 - Copyright 2015 ISA. All rights reserved. The following figures illustrate single acting and double acting actuator torque behavior: Figure 3 - Spring return torque curves Figure 4 - Double acting torque curve 3.5 break torque: the torque required t
24、o initiate movement of the valve closure member (i.e., ball, disc, or plug) from closed position to open position and from open position to close position 3.6 pressure (air) torque double acting (no spring): for double-acting actuators the end torque output is equal to the start torque output. 3.7 p
25、ressure (air) actuator opposed spring actuator torque (see Figure 3): a) Spring start: that torque output position at which a spring-return actuator produces its greatest torque output during a spring stroke. The starting torque output listed in the manufacturers spring-return - 13 - ANSI/ISA-96.03.
26、02-2015 Copyright 2015 ISA. All rights reserved. torque output charts; is that torque output position, where the spring is fully compressed, and capable of transferring its maximum force. b) Spring end: that torque output position, at which an actuator has reached the limit of the spring stroke. The
27、 spring ending torque output values listed on manufacturers spring-return torque output charts; is the torque output value where the spring is fully extended and is transferring its lowest force value. c) Air start: that torque output position at which a spring-return actuator produces its greatest
28、torque output during an air stroke. The starting torque output listed in the manufacturers spring-return torque output charts; is that torque output position, where the spring is fully extended. d) Air end: that torque output position, at which an actuator has reached the limit of the air stroke. Th
29、e air ending torque output values listed on manufacturers spring-return torque output charts; is the torque output value where the spring is fully compressed. 3.8 air supply: a suitable (preferably clean and dry) compressed gas supply to operate the actuator (see ISA-7.0.01 for quality air) 3.9 valv
30、e sizing torques (also see Clause 10): the nominal torque required to cycle the valve as supplied by the valve manufacturer. This shall be based upon a variety of factors including, but not limited to, the following factors: service conditions (e.g., maximum differential shutoff pressure, fluid medi
31、a, frequency of operation, etc.), valve type, valve seating type (soft seat or metal seat). 3.10 Maximum Allowable Stem Torque (MAST): the maximum allowable torque that can be applied to specific valve stem material prior to physical permanent damage 3.11 Maximum Operating Pressure (MOP): the maximu
32、m pressure that will be supplied to stroke an actuator (which must be compared to actuator MAOP) 3.12 Maximum Allowable Operating Pressure (MAOP): the pressure, which an actuator will operate normally, producing torque according to the published tables and torque curves 3.13 Maximum Allowable Workin
33、g Pressure (MAWP): the maximum pressure allowed at full stroke 4 Design requirements The main components of the rack and pinion actuator are as follows: a) Rack and piston b) Pinion gear c) Housing d) End caps e) Springs (if required) The actuator shall have an integral visual position indicator, sh
34、owing beginning and end of travel positions. ANSI/ISA-96.03.02-2015 - 14 - Copyright 2015 ISA. All rights reserved. Actuators shall have adjustable position stops to limit travel (e.g., +/- 2.5 to 5 degrees at each end). Jam nuts or lock nuts shall be utilized to prevent accidental adjustment of the
35、 travel stops. Spring return models shall incorporate an inherently safe spring design that allows the actuator to be safely assembled and disassembled in the field (caution tags must be included to identify spring enclosed mechanism). Single acting (e.g., spring return) rack and pinion actuators sh
36、all not be designed or specified to use compressed gas supply to increase the spring side output torque of the actuator. NOTE Consult the actuator manufacturer before using an air assist to ensure that using air pressure on the spring side will not overload the valve shaft, actuator or automation co
37、mponents (brackets, couplings, lock-in-place devices, etc.) resulting in damage. The actuator shall be capable of being mounted and operated in any orientation. NOTE User to specify actuator orientation when orientation critical control components will be furnished (e.g., filter regulator). The desi
38、gn shall provide for a suspension system of self-lubricating guide bands that eliminate metal-to-metal contact while providing low friction surfaces between all moving parts and the cylinder walls. Piston seals shall not be utilized to carry load. ISO 5211 or MSS SP-101 shall be followed for mountin
39、g actuators on valves. Accessory mounting shall comply with NAMUR VDI/VDE 3845. The actuator shall be designed to operate in both indoors and outdoors; be fully enclosed with no external mechanisms; and have a design safety factor ratio of 1.5: 1, between the maximum allowable working pressure and t
40、he maximum allowable operating pressure. The design shall be such that little or no maintenance is required. 5 Construction Aluminum materials used shall be low copper content (0.4% or less) and be acceptable for marine applications when specified by the user. Central drive shaft shall be constructe
41、d from a corrosion resistant alloy or be coated to protect from corrosion and be acceptable for marine applications when specified by the user. All springs shall be corrosion resistant or coated for corrosion resistance. Actuators powered by sour gas shall comply with NACE MR0175 / ISO 15156 ambient
42、 environmental conditions. 6 Manual overrides Jackscrew or gearbox overrides are acceptable methods for manual operation when specified. The manufacturer is responsible to ensure that operation of either type can be accomplished safely. The user shall examine ergonomics for suitability. The gearbox
43、shall be permanently sealed against atmospheric conditions or be provided with a means for periodic lubrication (see/reference MSS SP-91). 7 Corrosion protection Actuators shall be protected against external corrosion by proper material selection and/or surface treatment as well as be acceptable for
44、 use in a marine environment when specified by the user. If - 15 - ANSI/ISA-96.03.02-2015 Copyright 2015 ISA. All rights reserved. extreme or harsh environmental service conditions exist, the user shall communicate the existence of these conditions to enable the supplier to properly select corrosion
45、 protection. If a spring return actuator is installed in a harsh environment that could result in possible internal corrosion, then the user should consider a closed loop air supply system which will significantly reduce the ingress of ambient air into the cylinder that may cause corrosion to intern
46、al parts of the actuator. Piston spring chambers that can draw in atmopheric air should be resistant to enviroment contaminants. NOTE Consult the actuator manufacturer before using air assist to ensure that using air pressure on the spring side will not overload the valve shaft or actuator, resultin
47、g in damage. 8 Valve actuator mounting hardware The valve actuator mounting hardware is comprised of combinations of the following: intermediate support, coupling, drive key(s), dowel pin and bolting. The mounting hardware shall be designed with a load rating at least 10% greater than all combined l
48、oads it will have to support (design safety factor of 1.1 or higher). Example forces to be considered, in the design of mounting hardware, are listed below: Maximum actuator output torque generated at MAOP or as limited by a relief valve Maximum torque generated by a single acting actuators spring E
49、xternal loads (e.g., actuator weight, side loads from mounting orientations, etc.) Environmental loads (e.g., wind, snow, seismic activity) Speed of actuator operation that may cause shock loading To manage the high intertial impact load caused by high speed movement or a large mass the use of end cushion or hydraulic damper should be considered to protect the actuator at the end of its travel. NOTE User to specify other external loads that may affect mounting adaptation. Tensile stresses in mounting adaptation components shall not exceed 67% of Specified Minimum
